Tugtupite Antao S M, Hassan I, Parise J B American Mineralogist 89 (2004) 492-497 Tugtupite: High-temperature structures obtained from in situ synchrotron diffraction and Rietveld refinements T = 516 C _database_code_amcsd 0003457 8.66710 8.66710 8.8857 90 90 90 I-4 atom x y z Uiso Al 0 .5 .75 .0168 Be 0 .5 .25 .010 Si .0123 .2541 .4948 .0168 O1 .1500 .1374 .4464 .0188 O2 .3436 .0340 .6517 .0188 O3 .4304 .1450 .1393 .0188 Na .1602 .1977 .1828 .0471 Cl 0 0 0 .0585